[patch 7/8] KGDB support for x86_64
From: Tom Rini
Date: Fri Oct 29 2004 - 14:24:59 EST
Cc: Andi Kleen <ak@xxxxxxx>
This adds KGDB support for x86_64.
---
linux-2.6.10-rc1-trini/arch/x86_64/Kconfig.debug | 3
linux-2.6.10-rc1-trini/arch/x86_64/kernel/Makefile | 3
linux-2.6.10-rc1-trini/arch/x86_64/kernel/irq.c | 8
linux-2.6.10-rc1-trini/arch/x86_64/kernel/kgdb.c | 448 +++++++++++++++++++++
linux-2.6.10-rc1-trini/arch/x86_64/kernel/traps.c | 3
linux-2.6.10-rc1-trini/include/asm-x86_64/kgdb.h | 56 ++
linux-2.6.10-rc1-trini/lib/Kconfig.debug | 2
7 files changed, 518 insertions(+), 5 deletions(-)
diff -puN arch/x86_64/Kconfig.debug~x86_64-lite arch/x86_64/Kconfig.debug
--- linux-2.6.10-rc1/arch/x86_64/Kconfig.debug~x86_64-lite 2004-10-29 11:26:45.744147657 -0700
+++ linux-2.6.10-rc1-trini/arch/x86_64/Kconfig.debug 2004-10-29 11:26:45.757144605 -0700
@@ -41,7 +41,4 @@ config IOMMU_LEAK
Add a simple leak tracer to the IOMMU code. This is useful when you
are debugging a buggy device driver that leaks IOMMU mappings.
-#config X86_REMOTE_DEBUG
-# bool "kgdb debugging stub"
-
endmenu
diff -puN arch/x86_64/kernel/Makefile~x86_64-lite arch/x86_64/kernel/Makefile
--- linux-2.6.10-rc1/arch/x86_64/kernel/Makefile~x86_64-lite 2004-10-29 11:26:45.746147187 -0700
+++ linux-2.6.10-rc1-trini/arch/x86_64/kernel/Makefile 2004-10-29 11:26:45.757144605 -0700
@@ -10,6 +10,8 @@ obj-y := process.o semaphore.o signal.o
setup64.o bootflag.o e820.o reboot.o warmreboot.o
obj-y += mce.o
+CFLAGS_vsyscall.o := -g0
+
obj-$(CONFIG_MTRR) += ../../i386/kernel/cpu/mtrr/
obj-$(CONFIG_ACPI_BOOT) += acpi/
obj-$(CONFIG_X86_MSR) += msr.o
@@ -27,6 +29,7 @@ obj-$(CONFIG_DUMMY_IOMMU) += pci-nommu.o
obj-$(CONFIG_SWIOTLB) += swiotlb.o
obj-$(CONFIG_MODULES) += module.o
+obj-$(CONFIG_KGDB) += kgdb.o
obj-y += topology.o
obj-y += intel_cacheinfo.o
diff -puN arch/x86_64/kernel/irq.c~x86_64-lite arch/x86_64/kernel/irq.c
--- linux-2.6.10-rc1/arch/x86_64/kernel/irq.c~x86_64-lite 2004-10-29 11:26:45.748146718 -0700
+++ linux-2.6.10-rc1-trini/arch/x86_64/kernel/irq.c 2004-10-29 11:26:45.757144605 -0700
@@ -14,6 +14,7 @@
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/module.h>
+#include <linux/kgdb.h>
#include <asm/uaccess.h>
#include <asm/io_apic.h>
@@ -103,6 +104,13 @@ asmlinkage unsigned int do_IRQ(struct pt
__do_IRQ(irq, regs);
irq_exit();
+ /*
+ * Do not call breakpoint as on the x86_64 architecture if the
+ * exception tables are not set.
+ */
+ if(CHECK_EXCEPTION_STACK())
+ kgdb_process_breakpoint();
+
return 1;
}
diff -puN /dev/null arch/x86_64/kernel/kgdb.c
--- /dev/null 2004-10-25 00:35:20.587727328 -0700
+++ linux-2.6.10-rc1-trini/arch/x86_64/kernel/kgdb.c 2004-10-29 11:26:45.758144370 -0700
@@ -0,0 +1,448 @@
+/*
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ */
+
+/*
+ * Copyright (C) 2004 Amit S. Kale
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002 Andi Kleen, SuSE Labs
+ */
+/****************************************************************************
+ * Contributor: Lake Stevens Instrument Division$
+ * Written by: Glenn Engel $
+ * Updated by: Amit Kale<akale@xxxxxxxxxxx>
+ * Modified for 386 by Jim Kingdon, Cygnus Support.
+ * Origianl kgdb, compatibility with 2.1.xx kernel by David Grothe <dave@xxxxxxxx>
+ * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@xxxxxxx>
+ * X86_64 changes from Andi Kleen's patch merged by Jim Houston
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <asm/system.h>
+#include <asm/ptrace.h> /* for linux pt_regs struct */
+#include <linux/kgdb.h>
+#include <linux/init.h>
+#include <linux/debugger.h>
+#include <asm/kdebug.h>
+
+/* Put the error code here just in case the user cares. */
+int gdb_x86_64errcode;
+/* Likewise, the vector number here (since GDB only gets the signal
+ number through the usual means, and that's not very specific). */
+int gdb_x86_64vector = -1;
+
+extern atomic_t cpu_doing_single_step;
+
+void regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ gdb_regs[_RAX] = regs->rax;
+ gdb_regs[_RBX] = regs->rbx;
+ gdb_regs[_RCX] = regs->rcx;
+ gdb_regs[_RDX] = regs->rdx;
+ gdb_regs[_RSI] = regs->rsi;
+ gdb_regs[_RDI] = regs->rdi;
+ gdb_regs[_RBP] = regs->rbp;
+ gdb_regs[_PS] = regs->eflags;
+ gdb_regs[_PC] = regs->rip;
+ gdb_regs[_R8] = regs->r8;
+ gdb_regs[_R9] = regs->r9;
+ gdb_regs[_R10] = regs->r10;
+ gdb_regs[_R11] = regs->r11;
+ gdb_regs[_R12] = regs->r12;
+ gdb_regs[_R13] = regs->r13;
+ gdb_regs[_R14] = regs->r14;
+ gdb_regs[_R15] = regs->r15;
+ gdb_regs[_RSP] = regs->rsp;
+}
+
+struct task_struct *__switch_to(struct task_struct *prev_p,
+ struct task_struct *next_p);
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+ gdb_regs[_RAX] = 0;
+ gdb_regs[_RBX] = 0;
+ gdb_regs[_RCX] = 0;
+ gdb_regs[_RDX] = 0;
+ gdb_regs[_RSI] = 0;
+ gdb_regs[_RDI] = 0;
+ gdb_regs[_RBP] = 0;
+ gdb_regs[_PS] = 0;
+ gdb_regs[_PC] = (unsigned long)__switch_to;
+ gdb_regs[_R8] = 0;
+ gdb_regs[_R9] = 0;
+ gdb_regs[_R10] = 0;
+ gdb_regs[_R11] = 0;
+ gdb_regs[_R12] = 0;
+ gdb_regs[_R13] = 0;
+ gdb_regs[_R14] = 0;
+ gdb_regs[_R15] = 0;
+ gdb_regs[_RSP] = p->thread.rsp;
+}
+
+void gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ regs->rax = gdb_regs[_RAX];
+ regs->rbx = gdb_regs[_RBX];
+ regs->rcx = gdb_regs[_RCX];
+ regs->rdx = gdb_regs[_RDX];
+ regs->rsi = gdb_regs[_RSI];
+ regs->rdi = gdb_regs[_RDI];
+ regs->rbp = gdb_regs[_RBP];
+ regs->eflags = gdb_regs[_PS];
+ regs->rip = gdb_regs[_PC];
+ regs->r8 = gdb_regs[_R8];
+ regs->r9 = gdb_regs[_R9];
+ regs->r10 = gdb_regs[_R10];
+ regs->r11 = gdb_regs[_R11];
+ regs->r12 = gdb_regs[_R12];
+ regs->r13 = gdb_regs[_R13];
+ regs->r14 = gdb_regs[_R14];
+ regs->r15 = gdb_regs[_R15];
+#if 0 /* can't change these */
+ regs->rsp = gdb_regs[_RSP];
+ regs->ss = gdb_regs[_SS];
+ regs->fs = gdb_regs[_FS];
+ regs->gs = gdb_regs[_GS];
+#endif
+
+} /* gdb_regs_to_regs */
+
+struct hw_breakpoint {
+ unsigned enabled;
+ unsigned type;
+ unsigned len;
+ unsigned long addr;
+} breakinfo[4] = { {
+enabled:0}, {
+enabled:0}, {
+enabled:0}, {
+enabled:0}};
+
+void kgdb_correct_hw_break(void)
+{
+ int breakno;
+ int correctit;
+ int breakbit;
+ unsigned long dr7;
+
+ asm volatile ("movq %%db7, %0\n":"=r" (dr7):);
+ do {
+ unsigned long addr0, addr1, addr2, addr3;
+ asm volatile ("movq %%db0, %0\n"
+ "movq %%db1, %1\n"
+ "movq %%db2, %2\n"
+ "movq %%db3, %3\n":"=r" (addr0), "=r"(addr1),
+ "=r"(addr2), "=r"(addr3):);
+ } while (0);
+ correctit = 0;
+ for (breakno = 0; breakno < 3; breakno++) {
+ breakbit = 2 << (breakno << 1);
+ if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
+ correctit = 1;
+ dr7 |= breakbit;
+ dr7 &= ~(0xf0000 << (breakno << 2));
+ dr7 |= (((breakinfo[breakno].len << 2) |
+ breakinfo[breakno].type) << 16) <<
+ (breakno << 2);
+ switch (breakno) {
+ case 0:
+ asm volatile ("movq %0, %%dr0\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 1:
+ asm volatile ("movq %0, %%dr1\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 2:
+ asm volatile ("movq %0, %%dr2\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 3:
+ asm volatile ("movq %0, %%dr3\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+ }
+ } else if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
+ correctit = 1;
+ dr7 &= ~breakbit;
+ dr7 &= ~(0xf0000 << (breakno << 2));
+ }
+ }
+ if (correctit) {
+ asm volatile ("movq %0, %%db7\n"::"r" (dr7));
+ }
+}
+
+int kgdb_remove_hw_break(unsigned long addr)
+{
+ int i, idx = -1;
+ for (i = 0; i < 4; i++) {
+ if (breakinfo[i].addr == addr && breakinfo[i].enabled) {
+ idx = i;
+ break;
+ }
+ }
+ if (idx == -1)
+ return -1;
+
+ breakinfo[idx].enabled = 0;
+ return 0;
+}
+
+int kgdb_set_hw_break(unsigned long addr)
+{
+ int i, idx = -1;
+ for (i = 0; i < 4; i++) {
+ if (!breakinfo[i].enabled) {
+ idx = i;
+ break;
+ }
+ }
+ if (idx == -1)
+ return -1;
+
+ breakinfo[idx].enabled = 1;
+ breakinfo[idx].type = 1;
+ breakinfo[idx].len = 1;
+ breakinfo[idx].addr = addr;
+ return 0;
+}
+
+int remove_hw_break(unsigned breakno)
+{
+ if (!breakinfo[breakno].enabled) {
+ return -1;
+ }
+ breakinfo[breakno].enabled = 0;
+ return 0;
+}
+
+int set_hw_break(unsigned breakno, unsigned type, unsigned len, unsigned addr)
+{
+ if (breakinfo[breakno].enabled) {
+ return -1;
+ }
+ breakinfo[breakno].enabled = 1;
+ breakinfo[breakno].type = type;
+ breakinfo[breakno].len = len;
+ breakinfo[breakno].addr = addr;
+ return 0;
+}
+
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+ /* Disable hardware debugging while we are in kgdb */
+ asm volatile ("movq %0,%%db7": /* no output */ :"r" (0UL));
+}
+
+void kgdb_post_master_code(struct pt_regs *regs, int eVector, int err_code)
+{
+ /* Master processor is completely in the debugger */
+ gdb_x86_64vector = eVector;
+ gdb_x86_64errcode = err_code;
+}
+
+int kgdb_arch_handle_exception(int exceptionVector, int signo, int err_code,
+ char *remcomInBuffer, char *remcomOutBuffer,
+ struct pt_regs *linux_regs)
+{
+ unsigned long addr, length;
+ unsigned long breakno, breaktype;
+ char *ptr;
+ int newPC;
+ unsigned long dr6;
+
+ switch (remcomInBuffer[0]) {
+ case 'c':
+ case 's':
+ if (kgdb_contthread && kgdb_contthread != current) {
+ strcpy(remcomOutBuffer, "E00");
+ break;
+ }
+
+ /* try to read optional parameter, pc unchanged if no parm */
+ ptr = &remcomInBuffer[1];
+ if (kgdb_hex2long(&ptr, &addr)) {
+ linux_regs->rip = addr;
+ }
+ newPC = linux_regs->rip;
+
+ /* clear the trace bit */
+ linux_regs->eflags &= ~TF_MASK;
+
+ atomic_set(&cpu_doing_single_step,-1);
+ /* set the trace bit if we're stepping */
+ if (remcomInBuffer[0] == 's') {
+ linux_regs->eflags |= TF_MASK;
+ debugger_step = 1;
+ if (kgdb_contthread)
+ atomic_set(&cpu_doing_single_step,smp_processor_id());
+
+ }
+
+ asm volatile ("movq %%db6, %0\n":"=r" (dr6));
+ if (!(dr6 & 0x4000)) {
+ for (breakno = 0; breakno < 4; ++breakno) {
+ if (dr6 & (1 << breakno)) {
+ if (breakinfo[breakno].type == 0) {
+ /* Set restore flag */
+ linux_regs->eflags |= X86_EFLAGS_RF;
+ break;
+ }
+ }
+ }
+ }
+ kgdb_correct_hw_break();
+ asm volatile ("movq %0, %%db6\n"::"r" (0UL));
+
+ return (0);
+
+ case 'Y':
+ ptr = &remcomInBuffer[1];
+ kgdb_hex2long(&ptr, &breakno);
+ ptr++;
+ kgdb_hex2long(&ptr, &breaktype);
+ ptr++;
+ kgdb_hex2long(&ptr, &length);
+ ptr++;
+ kgdb_hex2long(&ptr, &addr);
+ if (set_hw_break(breakno & 0x3, breaktype & 0x3,
+ length & 0x3, addr) == 0) {
+ strcpy(remcomOutBuffer, "OK");
+ } else {
+ strcpy(remcomOutBuffer, "ERROR");
+ }
+ break;
+
+ /* Remove hardware breakpoint */
+ case 'y':
+ ptr = &remcomInBuffer[1];
+ kgdb_hex2long(&ptr, &breakno);
+ if (remove_hw_break(breakno & 0x3) == 0) {
+ strcpy(remcomOutBuffer, "OK");
+ } else {
+ strcpy(remcomOutBuffer, "ERROR");
+ }
+ break;
+
+ } /* switch */
+ return -1; /* this means that we do not want to exit from the handler */
+}
+
+static struct pt_regs *in_interrupt_stack(unsigned long rsp, int cpu)
+{
+ struct pt_regs *regs;
+ unsigned long end = (unsigned long)cpu_pda[cpu].irqstackptr;
+ if (rsp <= end && rsp >= end - IRQSTACKSIZE + 8) {
+ regs = *(((struct pt_regs **)end) - 1);
+ return regs;
+ }
+ return NULL;
+}
+
+static struct pt_regs *in_exception_stack(unsigned long rsp, int cpu)
+{
+ int i;
+ struct tss_struct *init_tss = &per_cpu(init_tss,get_cpu());
+ for (i = 0; i < N_EXCEPTION_STACKS; i++)
+ if (rsp >= init_tss[cpu].ist[i] &&
+ rsp <= init_tss[cpu].ist[i] + EXCEPTION_STKSZ) {
+ struct pt_regs *r =
+ (void *)init_tss[cpu].ist[i] + EXCEPTION_STKSZ;
+ return r - 1;
+ }
+ return NULL;
+}
+
+void kgdb_shadowinfo(struct pt_regs *regs, char *buffer, unsigned threadid)
+{
+ static char intr_desc[] = "Stack at interrupt entrypoint";
+ static char exc_desc[] = "Stack at exception entrypoint";
+ struct pt_regs *stregs;
+ int cpu = hard_smp_processor_id();
+
+ if ((stregs = in_interrupt_stack(regs->rsp, cpu))) {
+ kgdb_mem2hex(intr_desc, buffer, strlen(intr_desc));
+ } else if ((stregs = in_exception_stack(regs->rsp, cpu))) {
+ kgdb_mem2hex(exc_desc, buffer, strlen(exc_desc));
+ }
+}
+
+struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs, int threadid)
+{
+ struct pt_regs *stregs;
+ int cpu = hard_smp_processor_id();
+
+ if ((stregs = in_interrupt_stack(regs->rsp, cpu))) {
+ return current;
+ } else if ((stregs = in_exception_stack(regs->rsp, cpu))) {
+ return current;
+ }
+ return NULL;
+}
+
+struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid)
+{
+ struct pt_regs *stregs;
+ int cpu = hard_smp_processor_id();
+
+ if ((stregs = in_interrupt_stack(regs->rsp, cpu))) {
+ return stregs;
+ } else if ((stregs = in_exception_stack(regs->rsp, cpu))) {
+ return stregs;
+ }
+ return NULL;
+}
+
+/* Register KGDB with the die_chain so that we hook into all of the right
+ * spots. */
+static int kgdb_notify(struct notifier_block *self, unsigned long cmd,
+ void *ptr)
+{
+ struct die_args *d = ptr;
+
+ if (cmd == DIE_DEBUG && user_mode(d->regs))
+ return NOTIFY_STOP;
+ else if (cmd == DIE_NMI_IPI) {
+ if (atomic_read(&debugger_active))
+ debugger_nmihook(smp_processor_id(), ptr);
+ } else
+ CHK_DEBUGGER(d->trapnr, d->signr, d->err, d->regs,);
+
+ return NOTIFY_STOP;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_notify,
+ .priority = 0x7fffffff, /* we need to notified first */
+};
+
+int kgdb_arch_init(void)
+{
+ notifier_chain_register(&die_chain, &kgdb_notifier);
+ return 0;
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+ .gdb_bpt_instr = {0xcc},
+ .flags = KGDB_HW_BREAKPOINT,
+ .shadowth = 1,
+};
diff -puN arch/x86_64/kernel/traps.c~x86_64-lite arch/x86_64/kernel/traps.c
--- linux-2.6.10-rc1/arch/x86_64/kernel/traps.c~x86_64-lite 2004-10-29 11:26:45.750146248 -0700
+++ linux-2.6.10-rc1-trini/arch/x86_64/kernel/traps.c 2004-10-29 11:26:45.759144136 -0700
@@ -28,6 +28,7 @@
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
+#include <linux/debugger.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -642,7 +643,7 @@ asmlinkage void *do_debug(struct pt_regs
tsk->thread.debugreg6 = condition;
/* Mask out spurious TF errors due to lazy TF clearing */
- if (condition & DR_STEP) {
+ if (condition & DR_STEP && !debugger_step) {
/*
* The TF error should be masked out only if the current
* process is not traced and if the TRAP flag has been set
diff -puN /dev/null include/asm-x86_64/kgdb.h
--- /dev/null 2004-10-25 00:35:20.587727328 -0700
+++ linux-2.6.10-rc1-trini/include/asm-x86_64/kgdb.h 2004-10-29 11:26:45.759144136 -0700
@@ -0,0 +1,56 @@
+#ifndef _ASM_KGDB_H_
+#define _ASM_KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ */
+
+#include <linux/ptrace.h>
+
+/************************************************************************/
+/* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/
+/* at least NUMREGBYTES*2 are needed for register packets */
+/* Longer buffer is needed to list all threads */
+#define BUFMAX 1024
+
+/*
+ * Note that this register image is in a different order than
+ * the register image that Linux produces at interrupt time.
+ *
+ * Linux's register image is defined by struct pt_regs in ptrace.h.
+ * Just why GDB uses a different order is a historical mystery.
+ */
+
+enum regnames { _RAX,
+ _RDX,
+ _RCX,
+ _RBX,
+ _RSI,
+ _RDI,
+ _RBP,
+ _RSP,
+ _R8,
+ _R9,
+ _R10,
+ _R11,
+ _R12,
+ _R13,
+ _R14,
+ _R15,
+ _PC,
+ _PS,
+ _LASTREG = _PS
+};
+
+/* Number of bytes of registers. */
+#define NUMREGBYTES (_LASTREG*8)
+
+#define BREAKPOINT() asm(" int $3");
+#define BREAK_INSTR_SIZE 1
+
+/*
+ * Call kgdb_process_breakpoint() only if the interrupt and exception
+ * stacks of x86_64 are setup.
+ */
+#define CHECK_EXCEPTION_STACK() ((&per_cpu(init_tss, get_cpu ()))[0].ist[0])
+#endif /* _ASM_KGDB_H_ */
diff -puN lib/Kconfig.debug~x86_64-lite lib/Kconfig.debug
--- linux-2.6.10-rc1/lib/Kconfig.debug~x86_64-lite 2004-10-29 11:26:45.753145544 -0700
+++ linux-2.6.10-rc1-trini/lib/Kconfig.debug 2004-10-29 11:32:54.317581029 -0700
@@ -115,7 +115,7 @@ endif
config KGDB
bool "KGDB: kernel debugging with remote gdb"
- depends on DEBUG_KERNEL && (X86 || MIPS32 || IA64 || ((!SMP || BROKEN) && PPC32))
+ depends on DEBUG_KERNEL && (X86 || MIPS32 || IA64 || X86_64 || ((!SMP || BROKEN) && PPC32))
help
If you say Y here, it will be possible to remotely debug the
kernel using gdb. This enlarges your kernel image disk size by
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/